A recent aerial tour revealed plenty of greenery clinging to the banks of remote washes and streams, even if those lifelines carried little water to Phoenix’s reservoirs this spring.

It’s counterintuitive. You’d think that parched water channels would be barren and brown, not brimming with vegetation. But that’s what happens when the melting snow we need to refill our reservoirs doesn’t come: It doesn’t sweep small trees, bushes and plants away.

They cling to life with whatever trickle of water they can find. And the desert looks remarkably greener than it should.

Phoenix is remarkably resilient, too

CLOSE

How has one of the driest winters on record affected metro Phoenix's water supply? Let's take a helicopter tour to find out.
Wochit

The same could be said of metro Phoenix, which despite such a dry winter is barely showing the effects of it. Most of the reservoirs closest to town are nearly full.

The eight reservoirs operated by the Salt River Project – which supply a good portion of metro Phoenix’s drinking water – are still operating at nearly 60 percent of capacity. Water levels are down less than 20 percent from where they were last year, which was much wetter.

"In fact, we're more full now than almost two-thirds of the years" since the reservoirs were built, said Charlie Ester, who manages SRP's surface water resources.

It’s a stark contrast to Lake Mead, where the white “bathtub ring” gets larger seemingly by the day. That reservoir – a significant and critical water source for the state – is sinking ever closer to its first-ever shortage declaration, which would mean catastrophic cuts to the water that supplies Arizona’s underground water bank and Pinal County farms.

Why aren't we facing water shortages?

CLOSE

The Colorado River produces less water than Arizona and other states are entitled to use. And that is a big problem for our drinking water.

And that begs the question: Why is metro Phoenix so different?

Part of the answer lies in the way SRP's reservoirs were designed: Because they’re small, they can fill quickly. That means one wet winter, even if it’s sandwiched among several dry ones, can boost reservoir levels enough to leave us in relatively good short-term shape.

But that’s primarily because, unlike Lake Mead, metro Phoenix isn’t consistently sucking down more water than SRP's reservoirs produce. Water use has stayed relatively steady, even as our population has ballooned, because:

Houses use far less water than the farms that used to cover the Valley, and

"If you have a system where the surface water meets demand and your demand drops, you have a more resilient supply," Ester said.

That doesn't mean Phoenix can relax

A healthy forest should have 100 trees or less per acre, but this part of the Mogollon Rim has 10 times that many. You can see the overgrowth for miles as a heavy line of green.(Photo: Joanna Allhands/The Republic)

Does that mean we shouldn’t be alarmed about water? No. The problems at Lake Mead (not to mention fights around the state about limiting groundwater use and preserving rural water rights) are real and monumental for Arizona.

What’s more, SRP is compensating for the dry winter by using more unsustainable groundwater to conserve what’s in the reservoirs. Obviously, we can’t do that forever.

And there’s an even greater threat to the Phoenix area’s water supply, which comes full circle to that surprisingly green desert we have: Wildfire.

The forests in the upper elevations that feed metro Phoenix the slow, orderly snow melt we need to survive are clogged with trees. A devastating wildfire – one that kills off the oldest, tallest ponderosa pines on hundreds of thousands of acres across the watershed – isn’t just bad for the health of the forest.

Our more immediate water threat

And that rebirth takes years. In the meantime, the barren ground would be stripped when it rains and the snow melts, clogging our reservoirs and canals with debris and sediment that would make our water nearly undrinkable.

Ester says treating it to remove the muck would vastly increase water costs in the Phoenix area – not to mention shorten the life of the reservoirs on which we depend.

We simply must thin the forests, and once they’re thinner, reintroduce fire to clean them of the overgrowth that threatens us now. That’s how healthy forests work.

And it’s the only defense against the thing that – at least for now – threatens metro Phoenix’s water supply even more than historically bad winter droughts.